Technology spillovers and stability of international climate coalitions

Cooperation in international environmental agreements appears difficult to attain because of strong free-rider incentives. This paper explores how different technology spillover mechanisms among regions can influence the incentives to join and stabilise an international agreement. We use an applied modelling framework (STACO) that enables us to investigate the stability of partial climate coalitions. Several theories on the impact of technology spillovers are evaluated by simulating a range of alternative specifications. We find that spillovers are a good instrument to increase the abatement efforts of coalitions and reduce the associated costs. In our setting, however, they cannot overcome the strong free-rider incentives that are present in larger coalitions, i.e. technology spillovers do not substantially increase the success of international environmental agreements. This conclusion is robust with respect to the specification of technology spillovers.